[Mailman-Users] Microsoft blocking our Mailman lists

Stephen J. Turnbull turnbull.stephen.fw at u.tsukuba.ac.jp
Sun Oct 7 13:36:23 EDT 2018

Lindsay Haisley writes:

 >  hotmail-com.olc.protection.outlook.com []:
 >  >>> MAIL FROM:<aftm-bounces+clarkson-66=hotmail.com at lists.fmp.com>
 >  <<< 550 5.7.1 Unfortunately, messages from [] weren't
 > sent. Please contact your Internet service provider since part of their
 > network is on our block list (S3140). You can also refer your provider
 > to http://mail.live.com/mail/troubleshooting.aspx#errors.
 > [SN1NAM04FT034.eop-NAM04.prod.protection.outlook.com]
 > Has anyone seen similar problems recently with Microsoft mail customers
 > who are Mailman list subscribers?

Yes, I've seen a similar problem.  I was actually the source for a bit
of spam (backscatter from attempted subscriptions, fortunately those
lists don't need to be open subscription so I just blocked them all
with action DISCARD).

However, in my case it was specific to my IP, I was able to go to
their website and enter my IP into a "I won't do it again" page, and
after about 48 hours, mail was flowing again.  YMMV.

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